The present invention relates to the removal of particulate from a flow of ambient air, and more particularly to a vehicle air cleaner which provides a constant intake airflow velocity.
Vehicles commonly include an air cleaner system which removes particulate matter from airflow which is provided to a vehicle engine. Air cleaning is frequently achieved by cyclone-type devices which communicate intake airflow about a series of offset radiuses to separate out undesirable particles through centripetal acceleration.
Conventional cyclone-type devices must provide a high angular speed at low airflow to assure an angular speed sufficient to separate out the undesirable particles. The low airflow condition may be of particular concern as the vehicle is typically stationary or slowly moving and more likely to be surrounded by a large volume of undesirable particles. However, by designing the cyclone-type device to provide sufficient angular speed in the low airflow condition, the angular velocity through the cyclone-type device will be quite high when the vehicle is travelling at high speed. This high airflow condition generates a relatively large pressure drop across the air cleaner system which may decrease engine power through air starvation.
Accordingly, it is desirable to provide an air cleaner system which effectively removes particulate matter while maintaining a relative constant airflow velocity.
The vehicle air cleaner system according to the present invention includes a cyclone chamber. The particles are separated from the airflow through centripetal acceleration such that the relatively heavier undesirable particles are ejected through apertures in an outer surface of the cyclone chamber. A conventional media filter is located adjacent an outlet to provide additional filtration of the airflow prior to communication to a vehicle engine.
A variable inlet is located within the inlet to the cyclone chamber. The variable inlet communicates airflow to the cyclone chamber at a relatively constant velocity by varying an opening in response to airflow.
One variable inlet includes a piston which selectively restricts the inlet. During a relatively low airflow condition the piston is maintained toward a restricted position. The restricted position increases the angular velocity of the airflow by directing airflow toward smaller radii within the cyclone chamber. During a relatively high airflow condition the airflow through the variable inlet is directed toward the outer diameter of the cyclone chamber and larger radii to assure an angular speed sufficient to separate out undesirable particles yet prevent an undesirable pressure drop across the air cleaner system. By varying communication of airflow to particular radii within the cyclone chamber, a relatively constant pressure drop across the air cleaner system is provided regardless of airflow velocity.
Another variable inlet includes a movable valve which varies the variable inlet in response to a controller. During a high airflow condition, the valve is opened to lower the angular velocity of the airflow by directing airflow toward a larger radius. During a low airflow condition, the valve is closed to increase the angular velocity of the airflow by directing airflow toward the smaller radiuses. As the value is independently powered, the valve may be operated to compensate for conditions no directly related to airflow velocity.
The present invention therefore effectively removes particulate matter while maintaining a relative constant airflow velocity therethrough.